At maximum glide, when is the lift-to-drag ratio optimized?

At maximum glide, when is the lift-to-drag ratio optimized?

• A. Parasite drag is minimized
• B. Induced drag is zero
• C. Parasite drag equals induced drag
• D. Lift equals weight

Answer: (C)

When gliding in steady flight, you’re limited by how much drag your wing system has for the given weight, so maximizing the lift-to-drag ratio means minimizing the total drag for that lift. Parasite drag rises with speed, while induced drag falls with speed because generating lift with less downwash costs less induced drag at higher speeds. There is a specific speed where these two drag components balance, meaning parasite drag equals induced drag. At that point the total drag is minimized for the given lift, so the lift-to-drag ratio is maximized. That's why the optimal condition for best glide is when parasite drag equals induced drag.

When gliding in steady flight, you’re limited by how much drag your wing system has for the given weight, so maximizing the lift-to-drag ratio means minimizing the total drag for that lift. Parasite drag rises with speed, while induced drag falls with speed because generating lift with less downwash costs less induced drag at higher speeds. There is a specific speed where these two drag components balance, meaning parasite drag equals induced drag. At that point the total drag is minimized for the given lift, so the lift-to-drag ratio is maximized. That's why the optimal condition for best glide is when parasite drag equals induced drag.